Hippocampal Samples Research Articles

Gadd45A-mediated autophagy regulation and its impact on Alzheimer's disease pathogenesis: Deciphering the molecular Nexus

BackgroundThe growth arrest and DNA damage-inducible 45 (Gadd45) gene has been implicated in various central nervous system (CNS) functions, both normal and pathological, including aging, memory, and neurodegenerative diseases. In this study, we examined whether Gadd45A deletion triggers pathways associated with neurodegenerative diseases including Alzheimer's disease (AD). MethodsUtilizing transcriptome data from AD-associated hippocampus samples, we identified Gadd45A as a pivotal regulator of autophagy. Comprehensive analyses, including Gene Ontology enrichment and protein-protein interaction network assessments, highlighted Cdkn1A as a significant downstream target of Gadd45A. Experimental validation confirmed Gadd45A's role in modulating Cdkn1A expression and autophagy levels in hippocampal cells. We also examined the effects of autophagy on hippocampal functions and proinflammatory cytokine secretion. Additionally, a murine model was employed to validate the importance of Gadd45A in neuroinflammation and AD pathology. ResultsOur study identified 20 autophagy regulatory factors associated with AD, with Gadd45A emerging as a critical regulator. Experimental findings demonstrated that Gadd45A influences hippocampal cell fate by reducing Cdkn1A expression and suppressing autophagic activity. Comparisons between wild-type (WT) and Gadd45A knockout (Gadd45A−/−) mice revealed that Gadd45A−/− mice exhibited significant cognitive impairments, including deficits in working and spatial memory, increased Tau hyperphosphorylation, and elevated levels of kinases involved in Tau phosphorylation in the hippocampus. Additionally, Gadd45A−/− mice showed significant increases in pro-inflammatory cytokines and decreases autophagy markers in the brain. Neurotrophin levels and dendritic spine length were also reduced in Gadd45A−/− mice, likely contributing to the observed cognitive deficits. ConclusionsThese findings support the direct involvement of the Gadd45A gene in AD pathogenesis, and enhancing the expression of Gadd45A may represent a promising therapeutic strategy for the treatment of AD.

Centenarian hippocampus displays high levels of astrocytic metallothioneins.

The hippocampus is a brain area linked to cognition. The mechanisms that maintain cognitive activity in humans are poorly understood. Centenarians display extreme longevity which is generally accompanied by better quality of life, lower cognitive impairment, and reduced incidence of pathologies including neurodegenerative diseases. We performed transcriptomic studies in hippocampus samples from individuals of different ages (centenarians [≥97 years], old, and young) and identified a differential gene expression pattern in centenarians compared to the other two groups. In particular, several isoforms of metallothioneins (MTs) were highly expressed in centenarians. Moreover, we identified that MTs were mainly expressed in astrocytes. Functional studies in human primary astrocytes revealed that MT1 and MT3 are necessary for their homeostasis maintenance. Overall, these results indicate that the expression of MTs specifically in astrocytes is a mechanism for protection during aging.

Temporal variations in immune and inflammatory markers following rodent juvenile traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability in the juvenile population. TBI is associated with elevations in inflammatory signaling. However, the temporal changes in immune and inflammatory markers following TBI, particularly in juvenile studies utilizing the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA), have not been fully elucidated. The current study aimed to determine the time course of changes to immune cell expression throughout the first four days following juvenile TBI via the CHIMERA. Male Long Evans rats sustained either a TBI or a Sham TBI via the CHIMERA on post-natal day (PND) 30. Sham animals were euthanized at 3 hours (h) post-injury. TBI animals were euthanized at 0, 3, 6, 12, 24, or 96 h post-injury. Hippocampus samples were collected for use in QRT-PCR. The mRNA expression of cytokines IL1b and TNF-α was significantly elevated at 6 h, and C1q C chain (C1QC), a dendritic cell marker, was significantly elevated at 24 h. The mRNA expression of CD68, a marker for macrophages, was significantly elevated at 6, 24, and 96 h post-injury compared to Sham. CD3G, a marker for T cells, was significantly elevated at 6 hours post-injury. However, the mRNA expression of PTPRC, a marker for leukocytes, was not significantly altered throughout the time periods evaluated. To follow up on these studies, juvenile rats were injured and brains and blood were harvested 48 h post-injury comparing Sham and TBI. Peripheral blood lymphocytes were obtained and sorted by marker-specific antibodies. In the peripheral blood, there was a significantly higher number of CD3+ total T cells, CD3+/CD8 cytotoxic T cells, and CD3+/CD4+ helper T cells in the TBI group compared to the Sham, but CD45R+ total B cells and natural killer (NK) cells were not significantly different. Superior hemi-sected cortices were also used for immune cell extraction. There was a significantly lower number of NK cells and CD45R+ total B cells in the TBI group compared to the Sham, but CD45+ leukocytes and CD3+ total T cells were not significantly different. Further work is needed to understand the relationship between the reduction of specific cells in the brain with the elevation of cells in the peripheral blood. This work is supported by T32HL105324 to AMS. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Inhibiting the IRAK4/NF-κB/NLRP3 signaling pathway can reduce pyroptosis in hippocampal neurons and seizure episodes in epilepsy

BackgroundInterleukin-1 receptor-associated kinase 4 (IRAK4) plays an important role in immune modulation in various central nervous system disorders. However, IRAK4 has not been reported in epilepsy models in animal and clinical studies, nor has its involvement in regulating pyroptosis in epilepsy. MethodFirst, we performed transcriptome sequencing, quantitative real-time polymerase chain reaction, and western blot analysis on the hippocampal tissues of refractory epilepsy patients to measure the mRNA and protein levels of IRAK4 and pyroptosis-related proteins. Second, we successfully established a pentylenetetrazol (PTZ)-induced seizure mouse model. We conducted behavioral tests, electroencephalography, virus injection, and molecular biology experiments to investigate the role of IRAK4 in seizure activity regulation. ResultsIRAK4 is upregulated in the hippocampus of epilepsy patients and PTZ-induced seizure model mice. IRAK4 expression is observed in the hilar neurons of PTZ-induced mice. Knocking down IRAK4 in PTZ-induced mice downregulated pyroptosis-related protein expression and alleviated seizure activity. Overexpressing IRAK4 in naive mice upregulated pyroptosis-related protein expression and increased PTZ-induced abnormal neuronal discharges. IRAK4 and NF-κB were found to bind to each other in patient hippocampal tissue samples. Pyrrolidine dithiocarbamate reversed the pyroptosis-related protein expression increase caused by PTZ. PF-06650833 alleviated seizure activity and inhibited pyroptosis in PTZ-induced seizure mice. ConclusionIRAK4 plays a key role in the pathological process of epilepsy, and its potential mechanism may be related to pyroptosis mediated by the NF-κB/NLRP3 signaling pathway. PF-06650833 has potential as a therapeutic agent for alleviating epilepsy.

Cerebral and Peripheral Immune Cell Changes following Rodent Juvenile Traumatic Brain Injury.

Traumatic brain injury (TBI) is one of the leading causes of death and disability. TBI is associated with neuroinflammation, but temporal changes in immune and inflammatory signaling following TBI have not been fully elucidated. Furthermore, there have been no previous studies on changes in immune cell populations following TBI via the Closed Head Injury Model of Engineered Rotational Acceleration (CHIMERA). The current study aimed to determine the time course changes to inflammatory marker mRNA expression in the acute period following TBI in juvenile rats and to determine acute changes to brain and circulating immune cell populations. For this study, post-natal day (PND)-30 male Long Evans rats sustained a TBI or Sham TBI and were euthanized at 0, 3, 6, 12, 24, or 96 h post-injury. Prefrontal cortex and hippocampus samples were used to determine mRNA expression changes of inflammatory factors. The mRNA expression of the pro-inflammatory cytokine TNF-α was significantly elevated at 6 h post-injury in both regions evaluated. To evaluate immune cell populations, male Long Evans rats were euthanized at 48 h post-injury, and brain and blood samples were used for cell sorting by marker-specific antibodies. In the peripheral blood, there was an elevation in CD3+ total T cells, CD45R+ total B cells, and CD3+CD4+ helper T cells in the TBI subjects. However, there were no changes to natural killer cells or CD3+CD8+ cytotoxic T cell populations. In the brain, there was a reduction in CD11b/c+ monocytes/macrophages, but no changes in other immune cell populations. At 48 h post-injury, the TBI subjects also demonstrated expansion of the thymic medulla. These changes in the cerebral and blood immune cell populations and thymic medulla expansion may implicate the subacute recovery timeframe as a vulnerable window for the immune system in the pediatric population.

Network pharmacology and experimental evidence: ERK/CREB/BDNF signaling pathway is involved in the antidepressive roles of Kaiyu Zhishen decoction

Ethnopharmacological relevanceMajor Depressive Disorder (MDD) emerges as a complex psychosomatic condition, notable for its considerable suicidality and mortality rates. Increasing evidence suggests the efficacy of Chinese herbal medicine in mitigating depression symptoms and offsetting the adverse effects associated with conventional Western therapeutics. Notably, clinical trials have revealed the adjunctive antidepressant potential of Kaiyu Zhishen Decoction (KZD) alongside Western medication. However, the standalone antidepressant efficacy of KZD and its underlying mechanisms merit in-depth investigation. Aim of the studyThis research aims to elucidate the impact of KZD on MDD and delineate its mechanistic pathways through integrated network pharmacological assessments and empirical in vitro and in vivo analyses. Materials and methodsTo ascertain the optimal antidepressant dosage and mechanism of KZD, a Chronic Unpredictable Mild Stress (CUMS)-induced depression model in mice was established to evaluate depressive behaviors. High-Performance Liquid Chromatography (HPLC) and network pharmacological approaches were employed to predict KZD's antidepressant mechanisms. Subsequently, hippocampal samples were subjected to 4D-DIA proteomic sequencing and validated through Western blot, immunofluorescence, Nissl staining, and pathway antagonist applications. Additionally, cortisol-stimulated PC12 cells were utilized to simulate neuronal damage, analyzing protein and mRNA levels of MAPK-related signals and cell proliferation markers. ResultsThe integration of network pharmacology and HPLC identified kaempferol and quercetin as KZD's principal active compounds for MDD treatment. Proteomic and network pharmacological KEGG pathway analyses indicated the MAPK signaling pathway as a critical regulatory mechanism for KZD's therapeutic effect on MDD. KZD was observed to mitigate CUMS-induced upregulation of p-ERK/ERK, CREB, and BDNF protein expressions in hippocampal cells by attenuating oxidative stress, thereby ameliorating neuronal damage and exerting antidepressant effects. The administration of PD98059 counteracted KZD's improvements in depression-like behaviors and downregulated p-ERK/ERK and BDNF protein expressions in the hippocampus. ConclusionsThis investigation corroborates KZD's pivotal, dose-dependent role in antidepressant activity. Both in vivo and in vitro experiments demonstrate KZD's capacity to modulate the ERK-CREB-BDNF signaling pathway by diminishing ROS expression induced by oxidative stress, enhancing neuronal repair, and thus, manifesting antidepressant properties. Accordingly, KZD represents a promising herbal candidate for further antidepressant research.

The role of the cholinergic system in the memory-protecting effects of metformin in a model of scopolamine-induced memory impairment in aged rats

PurposeAs the elderly population grows, the prevalence of dementia is also rapidly increasing worldwide. Metformin, an antidiabetic drug, has been shown to have ameliorative effects on impaired cognitive functions in experimental models. However, studies have generally used young animals. Additionally, although it has a major role in Alzheimer's disease (AD) and memory, literature information about the effects of metformin on the cholinergic system is limited. In this study, we investigated the effects of metformin on memory in a model of scopolamine-induced memory impairment in aged rats. We also examined the effects of metformin on the cholinergic system, which is very important in cognitive functions. MethodsMetformin was administered orally to male Wistar rats (20–22 months old) at 100 mg/kg/day for three weeks. Morris water maze (MWM) tests were performed to assess spatial memory. Before the probe test of the MWM test, scopolamine was injected intraperitoneally at a dose of 1 mg/kg. After testing, animals were sacrificed, whole brains were removed, and hippocampus samples were separated for biochemical analysis. ResultsImpaired memory associated with scopolamine administration was reversed by metformin. In addition, metformin administration ameliorated scopolamine-induced changes in acetylcholine (ACh) levels, acetylcholinesterase (AChE), butyrylcholinesterase (BuChE), and choline acetyltransferase (ChAT) activity. ConclusionOur results show that metformin may have protective effects in a scopolamine-induced memory impairment model in aged animals by improving cholinergic function. Metformin shows promise in preventing dementia with its dual cholinesterase inhibition and ChAT activation effect.

LINC00472 Regulates Ferroptosis of Neurons in Alzheimer’s Disease via FOXO1

Introduction: The objective of the study was to explore the molecular mechanism of long noncoding RNA (lncRNA) LINC00472 in Alzheimer’s disease (AD) and identify potential novel targets for AD therapy. Method: Ferroptosis-related lncRNAs were screened by GEO database. AD mouse model was constructed for in vivo experiments. The content of Aβ protein and tau protein hyperphosphorylation were examined in hippocampal tissue samples of mice. Subsequently, HT22 cells were induced with Aβ25–35 to establish a neuronal injury model of AD in vitro. The expression of FOXO1, a key gene for ferroptosis, was verified by overexpressing/knocking down the LINC00472. The effects of LINC00472 on ROS and lipid peroxidation content, GPX4, and tau protein in AD model cells were examined by ROS assay, MDA assay, Western blot, and qRT-PCR. Subsequently, the expression of iron ion, FTH, TfRC, and Fpn protein were detected in AD cells. Results: The level of FOXO1 was positively correlated with the degree of AD. In vivo experiments showed that the expression of Aβ and tau hyperphosphorylated were significantly reduced in the inhibitor group and iron was significantly reduced relative to the AD group. In the AD cell model, the content of lipid peroxide was upregulated, GPX4 protein and mRNA were decreased, and phosphorylation of tau protein was enhanced in the AD cell model relative to the control group. Whereas knocking down LINC00472 inhibited the upregulation of lipid peroxide, decreased the level of GPX4, and enhanced tau protein phosphorylation, and reduced iron accumulation in AD cells. Conclusions: LINC00472 affects ferroptosis in AD by regulating iron accumulation in neuronal cells.

Ultrastructural analysis of synapses and mitochondria in the hippocampus of depressed patiens

IntroductionMajor depressive disorder (MDD) is a common multifactorial disorder, but the exact pathophysiology is still unknown. in vivo and post-mortem studies document volumetric and cellular changes in the hippocampus of depressed patients. Chemical synapses are key functional units of the central nervous system and earlier studies found reduced number of synapses in the prefrontal cortex of depressed patients (Kang HJ et al. Nature Medicine 2012;18(9):1413-1417). Mitochondria are intracellular powerhouses generating chemical energy for cellular biochemical reactions. Recent findings suggest that individuals with impaired mitochondrial function may be vulnerable to develop psychopathologies.ObjectivesWe investigated synapses and mitochondria in post-mortem hippocampal samples from psychiatric patients.MethodsThe three study groups were: 1) MDD patients (n=11); 2) patients with alcohol dependence (n=8) and 3) controls (n=10). Controls were individuals who accidentally deceased and had no neuropsychiatric disorders. Three sub-regions of the hippocampus (dentate gyrus, CA3 and CA1 areas were investigated. Ultrathin sections were examined, and photomicrographs were taken for further analysis using a JEOL JEM 1400 FLASH transmission electron microscope. Systematic quantitative analysis was conducted with the Neurolucida system using unbiased counting principles.ResultsWe could not detect any differences in synapse and mitochondria densities between the patients and controls subjects.ConclusionsOur preliminary data suggest that despite our expectations hippocampal synapse and mitochondrial densities are rather constant parameters which are not easily affected by psychopathology or alcohol consumption. Potential methodical limitations may also explain this negative finding.FUNDING:This research was founded by the Hungarian Brain Research Program 3 and by the TKP2021-EGA-16 project. A.S.T. was supported by the ÚNKP-23-3-I New National Excellence program of the Ministry for Culture and Innovation from the source of the National Research, Development and Innovation Fund.Disclosure of InterestNone Declared

Mild and deep hypothermia differentially affect cerebral neuroinflammatory and cold shock response following cardiopulmonary bypass in rat

IntroductionTargeted temperature management (TTM) is considered to be a neuroprotective strategy during cardiopulmonary bypass (CPB) assisted procedures, possibly through the activation of cold shock proteins. We therefore investigated the effects of mild compared with deep hypothermia on the neuroinflammatory response and cold shock protein expression after CPB in rats. MethodsWistar rats were subjected to 1 hr of mild (33 °C) or deep (18 °C) hypothermia during CPB or sham procedure. PET scan analyses using TSPO ligand [11C]PBR28 were performed on day 1 (short-term) or day 3 and 7 post-procedure (long-term) to assess neuroinflammation. Hippocampal and cortical samples were obtained at day 1 in the short-term group and at day 7 in the long-term group. mRNA expression of M1 and M2 microglia associated cytokines was analysed with RT-PCR. Cold shock protein RNA-binding motive 3 (RBM3) and tyrosine receptor kinase B (TrkB) receptor protein expression were determined with Western Blot and quantified. ResultsIn both groups target temperature was reached within an hour. Standard uptake values (SUV) of [11C]PBR28 in CPB rats at 1 day and 3 days were similar to that of sham animals. At 7 days after CPB the SUV was significantly higher in amygdala and hippocampal regions of the CPB 18 °C group as compared to the CPB 33 °C group. No differences were observed in the expression of M1 and M2 microglia-related cytokines between TTM 18 °C and 33 °C. RBM3 protein levels in cortex and hippocampus were significantly higher in CPB 33 °C compared to CPB 18 °C and sham 33 °C, at day 1 and day 7, respectively. ConclusionsTTM at 18 °C increased the neuroinflammatory response in amygdala and hippocampus compared to TTM at 33 °C in rats undergoing a CPB procedure. Additionally, TTM at 33 °C induced increased expression of TrkB and RBM3 in cortex and hippocampus of rats on CPB compared to TTM at 18 °C. Together, these data indicate that neuroinflammation is alleviated by TTM at 33 °C, possibly by recruiting protective mechanisms through cold shock protein induction.

Competing Endogenous RNAs Crosstalk in Hippocampus: A Potential Mechanism for Neuronal Developing Defects in Down Syndrome.

Down syndrome (DS) is the most example of aneuploidy, resulting from an additional copy of all or part of chromosome 21. Competing endogenous RNAs (ceRNAs) play important roles in neuronal development and neurological defects. This study aimed to identify hub genes and synergistic crosstalk among ceRNAs in the DS fetal hippocampus as potential targets for the treatment of DS-related neurodegenerative diseases. We profiled differentially expressed long non-coding RNAs (DElncRNAs), differentially expressed circular RNAs (DEcircRNAs), differentially expressed microRNAs (DEmiRNAs), and differentially expressed messenger RNAs (DEmRNAs) in hippocampal samples from patients with or without DS. Functional enrichment analysis and gene set enrichment analysis were performed, and chromosome 21-related ceRNA and protein-protein interaction networks were constructed. Additionally, the correlations between lncRNA-mRNA and miRNA-mRNA expression in the samples and HEK293T cells were validated. Our finding of changes in the expression of some key genes and ncRNAs on chromosome 21 in DS might not fully conform to the gene dosage hypothesis. Moreover, we found that four lncRNAs (MIR99AHG, PLCB4, SNHG14, GIGYF2) and one circRNA (hsa_circ_0061697) may competitively bind with three miRNAs (hsa-miR-548b-5p, miR-730-5p, and hsa-miR-548i) and subsequently regulate five mRNAs (beta-1,3-galactosyltransferase 5 [B3GALT5], helicase lymphoid-specific [HELLS], thrombospondin-2 [THBS2], glycinamide ribonucleotide transformylase [GART], clathrin heavy chain like 1 [CLTCL1]). These RNAs, whether located on chromosome 21 or not, interact with each other and might activate the PI3K/Akt/mTOR and Wnt signaling pathways, which are involved in autophagosome formation and tau hyperphosphorylation, possibly leading to adverse consequences of trisomy 21. These findings provide researchers with a better understanding of the fundamental molecular mechanisms underlying DS-related progressive defects in neuronal development.

IL-6 Enhances the Activation of PI3K-AKT/mTOR-GSK-3β by Upregulating GRPR in Hippocampal Neurons of Autistic Mice

Autism spectrum disorder (ASD) is a neurological disorder associated with brain inflammation. The underlying mechanisms could be attributed to the activation of PI3K signaling in the inflamed brain of ASD. Multiple studies highlight the role of GRPR in regulating ASD like abnormal behavior and enhancing the PI3K signaling. However, the molecular mechanism by which GRPR regulates PI3K signaling in neurons of individuals with ASD is still unclear. In this study, we utilized a maternal immune activation model to investigate the effects of GRPR on PI3K signaling in the inflamed brain of ASD mice. We used HT22 cells with and without GRPR to examine the impact of GRP-GRPR on the PI3K-AKT pathway with IL-6 treatment. We analyzed a dataset of hippocampus samples from ASD mice to identify hub genes. Our results demonstrated increased expression of IL-6, GRPR, and PI3K-AKT signaling in the hippocampus of ASD mice. Additionally, we observed increased GRPR expression and PI3K-AKT/mTOR activation in HT22 cells after IL-6 treatment, but decreased expression in HT22 cells with GRPR knockdown. NetworkAnalyst identified GSK-3β as the most crucial gene in the PI3K-AKT/mTOR pathway in the hippocampus of ASD. Furthermore, we found that IL-6 upregulated the expression of GSK-3β in HT22 cells by upregulating GRP-GRPR. Our findings suggest that IL-6 can enhance the activation of PI3K-AKT/mTOR-GSK-3β in hippocampal neurons of ASD mice by upregulating GRPR.Graphical

Complex Hippocampal Response to Thermal Skin Injury and Protocols with Hyperbaric Oxygen Therapy and Filipendula ulmaria Extract in Rats.

The aim of this study was to evaluate the alterations of the hippocampal function that may be related to anxiogenic response to thermal skin injury, including the morpho-functional alterations, and the effects of hyperbaric oxygen (HBO) and Filipendula ulmaria (FU) extract in the treatment of anxiety-like behavior that coincides with thermal skin injury. A rat thermal skin injury experimental model was performed on 2-month-old male Wistar albino rats. The evaluated therapeutic protocols included HBO and/or antioxidant supplementation. HBO was applied for 7 days in the hyperbaric chamber (100% O2, 2.5 ATA, 60 min). Oral administration of FU extract (final concentration of 100 mg/kg b.w.) to achieve antioxidant supplementation was also applied for 7 days. Anxiety level was estimated in the open field and elevated plus-maze test, which was followed by anesthesia, sacrifice, and collection of hippocampal tissue samples. HBO treatment and FU supplementation significantly abolished anxiogenic response to thermal skin injury. This beneficial effect was accompanied by the reduction in hippocampal pro-inflammatory and pro-apoptotic indicators, and enhanced BDNF and GABA-ARα2S gene expression, previously observed in untreated burns. The hippocampal relative gene expression of melatonin receptors and NPY positively responded to the applied protocols, in the same manner as µ and δ opioid receptors, while the opposite response was observed for κ receptors. The results of this study provide some confirmations that adjuvant strategies, such as HBO and antioxidant supplementation, may be simultaneously applied in the treatment of the anxiety-like behavior that coincides with thermal skin injury.

Neuroprotective Effect of Aurothioglucose-Loaded PLGA Nanoparticles in an Aluminum Chloride-Induced Rat Model of Alzheimer's Disease

Background: In Ayurvedic medicine, herbal, metallic, and herbometalic preparations gain recognition for treating physiological maladies. Aurothioglucose serves as a pharmaceutical intervention for the management of rheumatoid arthritis and can be potential as a potential pharmacological agent for mitigating neuronal toxicity. Objective: The current study was planned to explore the neuroprotective potential of aurothioglucose-loaded poly (lactic-co-glycolic acid) nanoparticles against aluminum chloride (AlCl3) induced Alzheimer's Disease. Method: In the in vivo study, AlCl3 (100 mg/kg, 21 days) was orally administered to rats, while, Aurothioglucose (ATG) and ATG NPs (Nanoparticles) (5, 10 mg/kg and 2.5 and 5 mg/kg, s.c.) were administered sub-cutaneous for a duration of 2 weeks. Following the treatment regimen, neurobehavioral evaluations were conducted utilizing the Open Field Test (OFT), Morris Water Maze (MWM), and Object Recognition Test (ORT). Subsequently, the rats were euthanized, and hippocampal tissue samples were procured for the assessment of biochemical and neuroinflammatory markers. Results: In the in-vivo experiment, the administration of both ATG and ATGNPs elicited a noteworthy reversal of cognitive impairments, biochemical perturbations, and neuroinflammatory markers induced by AlCl3. These observations suggest that ATG NPs demonstrate superior neuroprotective capabilities compared to ATG alone. Conclusion: The observed therapeutic outcomes imply that ATG and ATG NPs conferred amelioration against AlCl3-induced neurotoxicity in rats through mechanisms involving antioxidative and anti-inflammatory effects. Hence, ATG NPs could be a potential drug for correcting Alzheimer’s disease.

Increased levels of advanced oxidation protein products (AOPPs) were associated with nociceptive behavior and clinical scores in an experimental progressive autoimmune encephalomyelitis model (PMS-EAE).

Multiple sclerosis (MS) is a neurodegenerative disease that affects the central nervous system (CNS) generating neuropathic pain and anxiety. Primary progressive MS (PPMS) is the most disabling clinical form, and the patients present an intense neurodegenerative process. In this context, the advanced oxidation protein products (AOPPs) are oxidized compounds and their accumulation in plasma has been related to clinical disability in MS patients. However, the involvement of AOPPs in neuropathic pain- and anxiety-like symptoms was not previously evaluated. To assess this, female mice C57BL/6J were used to induce progressive experimental autoimmune encephalomyelitis (PMS-EAE). Clinical score, weight, strength of plantar pressure, rotarod test, mechanical allodynia, and cold hypersensitivity were evaluated before induction (baseline) and on days 7th, 10th, and 14th post-immunization. We assessed nest building, open field, and elevated plus-maze tests 13 days post-immunization. Animals were killed at 14 days post-immunization; then, AOPPs levels, NADPH oxidase, and myeloperoxidase (MPO) activity were measured in the prefrontal cortex, hippocampus, and spinal cord samples. The clinical score increased 14th post-immunization without changes in weight and mobility. Reduced paw strength, mechanical allodynia, and cold allodynia increased in the PMS-EAE animals. PMS-EAE mice showed spontaneous nociception and anxiety-like behavior. AOPPs concentration, NADPH oxidase, and MPO activity increase in CNS structures. Multivariate analyses indicated that the rise of AOPPs levels, NADPH oxidase, and MPO activity influenced the clinical score and cold allodynia. Thus, we indicated the association between non-stimuli painful perception, anxiety-like, and CNS oxidative damage in the PMS-EAE model.

Dietary Restriction Improves Perioperative Neurocognitive Disorders by Inhibiting Neuroinflammation and Gut Microbial Dysbiosis

Anesthesia/surgery have been identified as potential factors contributing to perioperative neurocognitive disorders, with a notably heightened risk observed in aging populations. One of the primary drivers of this impairment is believed to be neuroinflammation, specifically inflammation of hippocampal microglia. Dietary restriction has demonstrated a favorable impact on cognitive impairment across various disorders, primarily by quelling neuroinflammation. However, the precise influence of dietary restriction on perioperative neurocognitive disorders remains to be definitively ascertained. This investigation aims to explore the effects of dietary restriction on perioperative neurocognitive disorders and propose innovative therapeutic strategies for their management. The model of perioperative neurocognitive disorder was induced through exploratory laparotomy under isoflurane anesthesia. Cognitive performance was evaluated using the open field test, Barnes maze test, and fear conditioning test. The enzyme-linked immunosorbent assay (ELISA) was employed to quantify concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in both serum and hippocampal samples. The Western blot technique was utilized to assess expression levels of hippocampal PSD 95, Synaptophysin, TLR4, MyD88, and NF-kB p65. Microglial polarization was gauged using a combination of reverse transcription quantitative polymerase chain reaction (RT-qPCR) and immunofluorescence labeling techniques. We conducted 16S rRNA sequencing to investigate the impact of dietary restriction on the intestinal flora of aged mice following anesthesia/surgery. Our findings indicate that dietary restrictions have the potential to ameliorate anesthesia/surgery-induced cognitive dysfunction. This effect is achieved through the modulation of gut microbiota, suppression of inflammatory responses in hippocampal microglia, and facilitation of neuronal repair and regeneration.

Neuron-targeted exosome therapy: A novel approach for treating cardiogenic dementia via RyR2 inhibition

Cardiogenic dementia (CD), recognized since the late 1970s, manifests as altered consciousness and cognition due to heart conditions. Its elusive molecular mechanisms present diagnostic and management challenges. Emerging research implicates ryanodine receptor type 2 (RyR2) mediated intracellular Ca2 + leaks in myocardial infarction (MI)-linked cognitive impairment. We hypothesize that intravenous delivery of neuron-targeted exosomes loaded with RyR2-targeting siRNA (si-RyR2) to cerebral regions could rectify Ca2 + imbalance, curbing neurotoxic protein generation tied to CD. To investigate, si-RyR2 exosomes will be administered to MI-induced mice, with hippocampal samples analyzed for Ca2 + levels, β-amyloid, and p-tau. Results hold promise for advancing CD treatment insights.

An RNA-seq atlas of mouse brain areas during fasting and diet-induced obesity

Mammalian energy homeostasis is primarilly regulated by the hypothalamus and hindbrain, with the hippocampus, midbrain nuclei, and other regions implicated by evidence from human genetics studies. To understand how these non-canonical brain regions respond to imbalances in energy homeostasis, we performed two experiments examining the effects of different diets in male C57BL6 mice. In our first study, groups of six pair-housed mice were given access to chow, high-fat diet or fasted for 16 hours. In our subsequent study, two groups of 10 mice were single-housed and given access to chow or fasted for 24 h. We recorded food intake for each cage, the change in body weight for each animal, and collected hypothalamus, hippocampus, superior colliculus, inferior colliculus, frontal cortex, and zona incerta-centric samples. We performed bulk RNA sequencing on 185 samples and validated them by a series of quality control assessments including alignment quality and gene expression profiling. We believe these studies capture the transcriptomic effects of acute fasting and high-fat diet in the rodent brain and provide a valuable reference.

Intron retention as a productive mechanism in human MAPT: RNA species generated by retention of intron 3

Tau is a microtubule-binding protein encoded by the MAPT gene. Tau is essential for several physiological functions and associated with pathological processes, including Alzheimer's disease (AD). Six tau isoforms are typically described in the central nervous system, but current research paints a more diverse landscape and a more nuanced balance between isoforms. Recent work has described tau isoforms generated by intron 11 and intron 12 retention. This work adds to that evidence, proving the existence of MAPT transcripts retaining intron 3. Our aim is to demonstrate the existence of mature MAPT RNA species that retain intron 3 in human brain samples and to study its correlation with Alzheimer's disease across different regions. Initial evidence of intron-3-retaining MAPT species come from in silico analysis of RNA-seq databases. We further demonstrate the existence of these mature RNA species in a human neuroepithelioma cell line and human brain samples by quantitative PCR. We also use digital droplet PCR to demonstrate the existence of RNA species that retain either intron 3, intron 12 or both introns. Intron-3-retaining species are even more prominently present that intron-12-retaining ones. We show the presence of MAPT transcripts that retain both introns 3 and 12. These intron-retaining species are diminished in brain samples of patients with Alzheimer's disease with respect to individuals without dementia. Conversely, relative abundance of intron-3- or intron-12-retaining MAPT species with respect to double-retaining species as well as their percentage of expression with respect to total MAPT are increased in patients with Alzheimer's disease, especially in hippocampal samples. Among these TIR-MAPT species, TIR3+12 double truncation allows better classification potential of Alzheimer's disease samples. Moreover, we find a significant increase in intron-3- or intron-12-retaining species and its relative abundance with respect to double-retaining MAPT species in cerebellum in contrast to frontal lateral cortex and hippocampus in individuals with no signs of dementia. Intron retention constitutes a potential mechanism to generate Tau isoforms whose mature RNA expression levels correlate with Alzheimer's pathology showing its potential as a biomarker associated to the disease. This research was funded by the Spanish Ministry of Science, Innovation and Universities: PGC2018-096177-B-I00 (J.A.); Spanish Ministry of Science and Innovation (MCIN): PID2020-113204GB-I00 (F.H.) and PID2021-123859OB-100 from MCIN/AEI/10.13039/501100011033/FEDER, UE (J.A.). It was also supported by CSIC through an intramural grant (201920E104) (J.A.) and the Centre for Networked Biomedical Research on Neurodegenerative Diseases (J.A.). The Centro de Biología Molecular Severo Ochoa (CBMSO) is a Severo Ochoa Center of Excellence (MICIN, award CEX2021-001154-S).

APOE 5'UTR Methylation Pattern Analysis in Blood and Brain Tissue from Alzheimer's Disease Affected Patients.

APOE ε4 allele is the major genetic risk factor for Alzheimer's Disease (AD). Furthermore, APOE methylation pattern has been described to be associated with the disease and to follow a bimodal pattern, with a hypermethylated CpG island and a hypomethylated promoter region. However, little is known about the methylation levels in the APOE 5'UTR region. Here, the methylation of two regions (R1 and R2) within APOE 5'UTR was investigated in both peripheral blood mononuclear cells (PBMCs) and hippocampus (HIC) samples to identify differentially methylated CpG sites and to associate clinical, genetic features and cerebrospinal fluid (CSF) biomarkers levels. DNA was extracted from PBMCs of 20 AD and 20 healthy controls (HC) and from 6 AD and 3 HC HIC samples. The methylation analysis was carried out by means of pyrosequencing. In AD PBMCs we found that R1 region displayed a higher methylation level, while the opposite trend was observed in R2. The presence of ε4 allele highlighted a marked increase in R1 methylation level and a decrease in R2. In AD PBMCs and HIC, age progression resulted to be associated with an increase in the methylation level of R1. Lastly, the methylation of a CpG site in R2 was found to be related to CSF biomarkers. Despite the lack of a statistical significance, the outcome from this exploratory analysis highlighted the presence of a difference in methylation in APOE 5'UTR in PBMCs of AD patients which seemed to be associated also with APOE genotype, age and CSF biomarkers level.